Toronto's Lost Rivers include Christie Pits, Garrison Creek, Taddle Creek and dozens of other creeks and ravines. These 'lost rivers' are buried in large pipes and act as combined sewers for sanitary sewage and storm water. Combined sewer overflows are the single most urgent water problem in Toronto and cause flooding of combined sewage in our streets and basements and overflow in our ravines, parks and waterfront.

The discussion will be introduced by Prof. Lino Grima, School of the Environment, University of Toronto and Sierra Club Canada's Special Advisor on Water.